Литература / UMTS-Report

Does the SRTT use frequency hopping ? If so characterize and explain particularly the

impact (e.g. improvements) on system performance.

Frequency hopping is an option of the system to improve performances when sufficient

spectrum is available to the operator.

The advantages are twofolds :

- better performances for low-velocity mobiles, as frequency hopping allows terminal to

escape from a fadded frequency,

- interference diversity, it might allow a reuse factor of 1 if sufficient frequency is

available.

What is the hopping rate ?

It is the frame rate, that is to say 216 Hz (unless the timeslot rate, 1387 Hz, is felt

preferable for multislot allocation).

What is the number of the hopping frequency sets ?

To be Completed.

Are base stations synchronized or non-synchronized ?

Base stations are normally non-synchronized. A synchronised mode might however be

considered to ease monitoring of adjacent cells when discontinuous BCCH is used.

Does the SRTT use spreading scheme ?

No

What is the chip rate (Mchip/s) : Rate at input to modulator.

Not applicable to TDMA.

What is the processing gain : 10 log (Chip rate / Information rate).

Not applicable to this SRTT.

Explain the uplink and downlink code structures and provide the details about the types

(e.g. PN code, Walsh code) and purposes (e.g. spreading, identification, etc.) of the codes.

Not applicable to this SRTT.

Which access technology does the proposal use : TDMA, FDMA, CDMA , hybrid, or a

new technology ?

FDMA / TDMA.

In the case of CDMA which type of CDMA is used : Frequency Hopping (FH) or Direct

Sequence (DS) or hybrid ? Characterize.

Not applicable to this SRTT.

What is the baseband modulation technique ? If both the data modulation and spreading

modulation are required, please describe detail.

Two modulations are considered, depending on the bit-rate and the environment : Binary

Offset QAM (B-OQAM) and Quaternary Offset QAM (Q-OQAM) with a rolloff of 0.35.

What is the peak to average power ratio after baseband filtering (dB) ?

To be completed.

What are the channel coding (error handling) rate and form for both the forward and

reverse links ? e.g.

- Does the SRTT adopt FEC (Forward Error Correction) or other schemes ?

Circuit switched sercices can be protected by convolutional or turbo codes. Convolutional

codes can be punctered to efficiently achieve adaptive coding rate.

Packet services can be protected by ARQ schemes.

- Does the SRTT adopt unequal error protection ? Please provide details.

This is not considered but can be supported.

- Does the SRTT adopt soft decision decoding or hard decision decoding ? Please provide

details.

Soft decision decoding is adopted to take profit of the several dB of gain achievable by

Viterbi decoding of convolutional codes.

- Does the SRTT adopt iterative decoding (e.g. turbo codes) ? Please provide details.

Iterative decoding is considered for Turbo codes. The number of iteration is still opened.

- Other schemes.

What is the bit interleaving scheme ? Provide detailed description for both up link and

down link.

Interslot interleaving is provided whenever possible. The interleaving depth can be

adjusted to optimise trade-off between bearer C/I requirement and delay.

Describe the taken approach for the receivers (MS and BS) to cope with multipath

propagation effects (e.g. via equalizer, RAKE receiver, etc.).

An equalizer is assumed to combat multipath propagation. Training sequences have been

inserted in bursts for that purpose.

Describe the robustness to intersymbol interference and the specific delay spread profiles

that are best or worst for the proposal.

Large delay spreads can be tolerated by definition of bursts with long enough training

sequences.

If there is residual ISI after equalizer, it is handled by link adaptation and ARQ.

Performance degradation is graceful as delay spread increases. Also Vehicular B channel

can be supported with a small degradation in performance with the current burst structure.

With longer training sequences and flexible burst structure the performance could be

improved.

Can rapidly changing delay spread profile be accommodated ? Please describe.

Simulations show that there is no degradation for 1/64 slot up to 500 km/h. The question is

still opened for other slots.

What is the Adjacent channel protection ratio ?

To be completed.

In order to maintain robustness to adjacent channel interference, the SRTT should have

some receiver characteristics that can withstand higher power adjacent channel

interference. Specify the maximum allowed relative level of adjacent RF channel power in

dBc. Please provide detail how this figure is assumed.

To be Completed.

Power classes

To be completed.

Mobile terminal emitted power : What is the radiated antenna power measured at the

antenna ? For terrestrial component, please give (in dBm). For satellite component, the

mobile terminal emitted power should be given in EIRP (dBm).

To be completed

What is the maximum peak power transmitted while in active or busy state ?

A peak power limit of 1W is assumend for hand portables.

What is the time average power transmitted while in active or busy state ? Provide

detailed explanation used to calculate this time average power.

The average power of MS depends on power control settings and number of timeslots used..

Base station transmit power per RF carrier for terrestrial component

To be completed.

What is the maximum peak transmitted power per RF carrier radiated from antenna ?

To be completed.

What is the average transmitted power per RF carrier radiated from antenna ?

To be completed.

What is the maximum number of voice channels available per RF channel that can be

supported at one base station with 1 RF channel (TDD systems) or 1 duplex RF channel

pair (FDD systems), while still meeting G.726 performance requirements ?

64 channels can be supported per carrier of 1.6 MHz. It is however not possible at that

level to precise whether G.726 performance requirements are met.

What are the user information bit rates in each variable bit rate mode ?

Basically the protocol is capable of supporting any bitrate restricted by the granularity of

channel allocations. Currently the transmission capacity allocation granularity to RT a

service is of order 200 bit/s and the smallest allocable packet size for NRT bearer is of

order 250 bits (both figures are gross rates thus including channel coding).

For practical reasons it is considered currently to limit the set of possible bitrates for each

RT bearer to a set of 16 alternatives, which can be freely selected to each bearer separately

taking into account the above mentioned granularity. The bearer can change between these

agreed bitrates dynamically during transmission. For all NRT bearers all packet sizes

starting from 250 bits are available..

What kind of voice coding scheme or CODEC is assumed to be used in proposed SRTT ?

If the existing specific voice coding scheme or CODEC is to be used, give the name of it. If

a special voice coding scheme or CODEC (e.g. those not standardised in standardisation

bodies such as ITU) is indispensable for the proposed SRTT, provide detail, e.g. scheme,

algorithm, coding rates, coding delays and the number of stochastic code books.

Does the proposal offer multiple voice coding rate capability ? Please provide detail.

The protocol for resource allocation handles multiple voice coding rates similarly as any

other variable bitrate services. The realisation of multiple source coding rates is however

out of the scope of the radio interface.

Data services : Are there particular aspects of the proposed technologies which are

applicable for the provision of circuit-switched, packet-switched or other data services like

asymmetric data services ? For each service class (A, B, C and D) a description of SRTT

services should be provided, at least in terms of bit rate, delay and BER/FER.

TDD mode is of particular interest for asymmetric data service. The ratio of the channel

allocated to uplink and downlink can be dynamically changed as a function of the traffic

need.

For delay unconstrained, connection oriented. (Class C)

The proposed concept is capable to reliable transmission of data in any packet size with

guaranteed almost arbitrary quality and unconstrained delay. Also tradeoff on the quality

target and the delay requirement target can be handled. (See A.1.2.18).

For delay unconstrained, connectionless. (Class D)

To be Completed.

Simultaneous voice/data services : Is the proposal capable of providing multiple user

services simultaneously with appropriate channel capacity assignment ?

Multiple timeslot allocation can provide simultaneous voice/data service.

Note : The followings describe the different techniques that are inherent or improve to a

great extent the technology described above to be presented :

Description for both BS and MS are required in attributes from A2..22 through A1.2.23.2.

Power control characteristics : Is power control scheme included in the proposal ?

Characterise the impact (e.g. improvements) of supported power control schemes on system

performance.

The scheme includes two power control options.

1) Slow power control by dedicated power control messages

-Slow power control is applicable for both uplink and downlink power control. The concept

provides messages enabling both bearer specific and MS specific power control. The power

control interval of this scheme can be arbitrary (>4.615 ms) or can be applied only on

demand. The needed amount of power control signalling is highly dependent on the system

design, i.e. how large interference variations the system is able to handle.'

2) Public Power control for uplink

-This option enables controlling the power of each physical channel separately with 4,6 ms

interval. This method is only applicable for controlling the uplink powers..

What is the power control step size in dB ?

A step size of 0.5 dB to 4.0 dB is considered.

What are the number of power control cycles per second ?

Adjustable for each MS separately and can be dynamically varied during connection. See A.1.2.22.

What is the power control dynamic range in dB ?

A slow power control scheme is considered, with a dynamic range of 50 dB.

What is the minimum transmit power level with power control ?

To be Completed.

What is the residual power variation after power control when SRTT is operating ? Please

provide details about the circumstances (e.g. in terms of system characteristics,

environment, deployment, MS-speed, etc.) under which this residual power variation

appears and which impact it has on the system performance.

To be Completed.

Diversity combining in mobile station and base station : Are diversity combining schemes

incorporated in the design of the SRTT ?

Frequency and time diversity are considered both at the base station and at the mobile,

through frequency hopping, interleaving and possibly timeslot hopping.

Antenna diversity combining is possible and considered at the base station. It is possible

but not considered at the mobile station.

Describe the diversity techniques applied in the mobile station and at the base station ,

including micro diversity and macro diversity, characterizing the type of diversity used, for

example :

- time diversity

repetition, RAKE-receiver, etc.,

- space diversity

multiple sectors, multiple satellite, etc.,

- frequency diversity

FH, wideband transmission, etc.,

- code diversity

multiple PN codes, multiple FH code, etc.,

- other scheme.

Frequency and time hopping are considered.

Characterize the diversity combining algorithm, for example, switch diversity, maximal

ratio combining, equal gain combining. Additionally, provide supporting values for the

number of receivers (or demodulators) per cell per mobile user. State the dB of

performance improvement introduced by the use of diversity.

For the mobile station : what is the minimum number of RF receivers (or demodulators)

per mobile unit and what is the minimum number of antennas per mobile unit required for

the purpose of diversity reception ?

One RF receiver and one antenna are considered at the mobile unit.

These numbers should be consistent to that assumed in the link budget template in Annex 2

and that assumed in the calculation of the “capacity” defined at A1.3.1.5.

What is the degree of improvement expected in dB ? Please also indicate the assumed

condition such as BER and FER.

To be Completed.

Handover/Automatic Radio Link Transfer (ALT) : Do the radio transmission technologies

support handover ?

Characterize the type of handover strategy (or strategies) which may be supported, e.g.

mobile station assisted handover. Give explanations on potential advantages, e.g. possible

choice of handover algorithms. Provide evidence whenever possible.

Mobile assistd, seamless handover is considered.

What is the break duration (sec) when a handover is executed ? In this evaluation, a

detailed description of the impact of the handover on the service performance should also

be given. Explain how the estimate derived.

Seamless handover is considered

For the proposed SRTT, can handover cope with rapid decrease in signal strength (e.g.

street corner effect) ?

Give a detailed description of

- the way the handover detected, initiated and executed,

- how long each of this action lasts (minimum/maximum time in msec),

- the timeout periods for these actions.

To be Completed.

Characterize how does the proposed SRTT react to the system deployment in terms of the

evolution of coverage and capacity (e.g. necessity to add new cells and/or new carriers) :

- in terms of frequency planning

- in terms of the evolution of adaptive antenna technology using mobile identity codes (e.g.

sufficient number of channel sounding codes in a TDMA type of system)

- other relevant aspects

To be Completed.

Sharing frequency band capabilities : To what degree is the proposal able to deal with

spectrum sharing among UMTS systems as well as with all other systems :

- spectrum sharing between operators

- spectrum sharing between terrestrial and satellite UMTS systems

- spectrum sharing between UMTS and non-UMTS systems

- spectrum sharing between private and public UMTS operators

- other sharing schemes.

To be Completed.

Dynamic channel allocation : Characterize the DCA schemes which may be supported and

characterize their impact on system performance (e.g. in terms of adaptability to varying

interference conditions, adaptability to varying traffic conditions, capability to avoid

frequency planning, impact on the reuse distance, etc.)

See section 5.3.

Mixed cell architecture : How well do the technologies accommodate mixed cell

architectures (pico, micro and macrocells) ? Does the proposal provide pico, micro and

macro cell user service in a single licensed spectrum assignment, with handoff as required

between them ? (terrestrial component only)

To be Completed.

Note : Cell definitions are as follows :

pico - cell hex radius ® < 100 m

micro - 100 m < ® < 1000 m

macro - ® > 1000 m

Describe any battery saver / intermittent reception capability

To be Completed.

Ability of the mobile station to conserve standby battery power : Please provide details

about how the proposal conserve standby battery power.

To be Completed.

Signaling transmission scheme : If the proposed system will use radio transmission

technologies for signaling transmission different from those for user data transmission,

describe details of signaling transmission scheme over the radio interface between

terminals and base (satellite) stations.

The same transmission scheme is anticipated for data and signaling.

Describe the different signaling transfer schemes which may be supported, e.g. in

connection with a call, outside a call.

Does the SRTT support new techniques ? Characterise.

Does the SRTT support signalling enhancements for the delivery of multimedia services ?

Characterise.

See section 4.

Does the SRTT support a Bandwidth on Demand (BOD) capability ? Bandwidth on

Demand refers specifically to the ability of an end-user to request multi-bearer services.

Typically this is given as the capacity in the form of bits per second of throughput. Multi

bearer services can be implemented by using such technologies as multi carrier, multi time

slot or multi codes. If so, characterise these capabilities.

BOD can be accommodated by multi time slot allocation.

Note : BOD does not refer to the self-adaptive feature of the radio channel to cope with

changes in the transmission quality (see A1.2.5.1).

Does the SRTT support channel aggregation capability to achieve higher user bit rates ?

Not considered.

Expected Performances

for terrestrial test environment only

See section 7.

What is the achievable BER floor level (for voice) ?

Note : BER floor level under BER measuring condition defined in Annex 2 using the data

rates indicated in section 1 of Annex 2.

See section 7

What is the achievable BER floor level (for data) ?

Note : BER floor level under BER measuring condition defined in Annex 2 using the data

rates indicated in section 1 of Annex 2.

See section 7

What is the maximum tolerable delay spread (in nsec) to maintain the voice and data

service quality requirements ?

Note : The BER is an error floor level measured with the Doppler shift given in the BER

measuring conditions of ANNEX 2.

See section 7

What is the maximum tolerable doppler shift (in Hz) to maintain the voice and data service

quality requirements ?

Note : The BER is an error floor level measured with the delay spread given in the BER

measuring conditions of ANNEX 2.

See section 7

Capacity : The capacity of the radio transmission technology has to be evaluated assuming

the deployment models described in ANNEX 2 and technical parameters from A1.2.22

through A1.2.23.2.

See section 7.7

What is the voice traffic capacity per cell (not per sector) : Provide the total traffic that can

be supported by a single cell in Erlangs/MHz/cell in a total available assigned non-

contiguous bandwidth of 30 MHz (15 MHz forward/15 MHz reverse) for FDD mode or

contiguous bandwidth of 30 MHz for TDD mode. Provide capacities considering the model

for the test environment in ANNEX 2. The procedure to obtain this value in described in

ANNEX 2. The capacity supported by not a standalone cell but a single cell within

contiguous service area should be obtained here.

See section 7.7.

What is the information capacity per cell (not per sector) : Provide the total number of

user-channel information bits which can be supported by a single cell in Mbps/MHz/cell in

a total available assigned non-contiguous bandwidth of 30 MHz (15 MHz forward / 15

MHz reverse) for FDD mode or contiguous bandwidth of 30 MHz for TDD mode. Provide

capacities considering the model for the test environment in ANNEX 2. The procedure to

obtain this value in described in ANNEX 2. The capacity supported by not a standalone cell

but a single cell within contiguous service area should be obtained here.

See section 7.7

Does the SRTT support sectorization ? If yes, provide for each sectorization scheme and

the total number of user-channel information bits which can be supported by a single site in

Mbps/MHz (and the number of sectors) in a total available assigned non-contiguous

bandwidth of 30 MHz (15 MHz forward/15 MHz reverse) in FDD mode or contiguous

bandwidth of 30 MHz in TDD mode.

The SRTT supports sectorization.

Coverage efficiency : The coverage efficiency of the radio transmission technology has to

be evaluated assuming the deployment models described in ANNEX 2.

See annex 2.

What is the base site coverage efficiency in Km2/site for the lowest traffic loading in the

voice only deployment model ? Lowest traffic loading means the lowest penetration case

described in ANNEX 2.

To be Completed.

What is the base site coverage efficiency in Km2/site for the lowest traffic loading in the

data only deployment model ? Lowest traffic loading means the lowest penetration case

described in ANNEX 2.

To be Completed.

for satellite test environment only

Not applicable to this phase of the study of the SRTT